Spectres d’absorption du protactinium en solution aqueuse

Guillaumont, R.; Muxart, R.; Bouissieres, G.; Haissinsky, M.

doi:10.1051/jcp/1960571019

Cited by 28 publications

(43 citation statements)

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“…Therefore, the use of intermediate HF concentrations in the extraction chromatography experiments is not expected to have a significant effect on the outcome of the comparison of the Ha data with the Ta, Nb, Pa, and Zr/Hf data that is shown in Fig. 2 4 X] where X = F~ or CI" have been proposed [9,10].…”

Section: Resultsmentioning

confidence: 99%

Chemical Properties of Element 105 in Aqueous Solution: Back Extraction from Triisooctyl Amine into 0.5 M HCl

et al. 1993

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Previous studies of the halide complex formation of element 105 and its anion exchange with triisooctyl amine (TIOA) were continued. The experiments were performed on a one-minute time scale with the computer-controlled liquid chromatography system ARCA II on a mixture of 34-s 262 Ha and 27-s 263 Ha produced in the 249 Bk( 18 0,5n) and 249 Bk( 18 0,4n) reactions at a beam energy of 99 MeV. The Ha isotopes were detected by measuring the spontaneous fission and α-activities associated with their decay, and the α-decays of their daughters, 4-s 258 Lr, and 6-s 259 Lr. Time-correlated pairs of parent and daughter α-particles were also registered. 262,263 Ha was absorbed on the TIOA columns from either 12 M HCl/0.01 M HF or 10 M HCl, and was subsequently eluted in 0.5 M HCl/0.01 M HF like its homolog niobium, and the pseudohomolog protactinium, and unlike the closest homolog, tantalum, which remains in the amine phase under these conditions. The effluent was divided into an early Pa fraction and a subsequent Nb fraction. By varying the cut between the Pa fraction and the Nb fraction in rough steps, it was shown that the elution of element 105 occurs closer to the Pa elution position, i.e., earlier than the elution of Nb. These results confirm the non-tantalum like behavior of element 105 in 0.5 M HCl/0.01 M HF, and corroborate previously suggested structural differences between the halide complexes of element 105, niobium, and protactinium, on the one hand, and those of tantalum on the other hand.

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Section: Resultsmentioning

confidence: 99%

Chemical Properties of Element 105 in Aqueous Solution: Back Extraction from Triisooctyl Amine into 0.5 M HCl

et al. 1993

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“…Using the estimates of q for the oxychloride anions of Nb, Ha, and Pa, the strength of the associated complexes at high HCl concentrations due to the electrostatic interaction will be : A: ass (NbOClD > A^HaOCli") > Kass(PaOCir) · (10) In analogy for the intermediate HCl molarities * ass (NbOCl 4 ) > £ ass (HaOCl 4 ) > K ass (PaOCl 4 ), Table 3 the q 0 in Nb, Ha, and Pa complexes are -0.47, -0.49, and -0.51, respectively. Thus, the hydrogen bonding is the strongest in the protactinium associated complex and the weakest in the niobium one.…”

Section: Experimental [9] Distribution Coefficients For Nb Andmentioning

confidence: 99%

The Electronic Structure of Anionic Halide Complexes of Element 105 in Aqueous Solutions and Their Extraction by Aliphatic Amines

et al. 1994

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Element 105 / Hahnium / Chemical properties / Group 5 elements / Relativistic molecular orbital calculations AbstractTo study the complex formation of group 5 elements (Nb, Ta, Ha, and pseudoanalog Pa) in aqueous HCl solutions of medium and high concentrations the electronic structures of anionic complexes of these elements [MC1 6 ]~, [MOCLJ", [M(OH) 2 Cl 4 ]~, and [MOCI5] 2 " have been calculated using the relativistic DiracSlater Discrete-Variational Method. The charge density distribution analysis has shown that tantalum occupies a specific position in the group and has the highest tendency to form the pure halide complex, [TaCl 6 ] ~. This fact along with a high covalency of this complex explains its good extractability into aliphatic amines. Niobium has equal trends to form pure halide [NbCl 6 ]~ and oxyhalide [NbOCl 5 ] 2 " species at medium and high acid concentrations. Protactinium has a slight preference for the [PaOCl 5 ] 2-form or for the pure halide complexes with coordination number higher than 6 under these conditions. Element 105 at high HCl concentrations will have a preference to form oxyhalide anionic complex [HaOCl 5 ] 2~ rather than [HaCl 6 ] ". For the same sort of anionic oxychloride complexes an estimate has been done of their partition between the organic and aqueous phases in the extraction by aliphatic amines, which shows the following succession of the partition coefficients: Ρ Nb < Phu < ipa·

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“…The separated 233 Pa was dried and dissolved in 1 M NaC10 4 and the pH was adjusted to 0.2 using HCIO4. At such conditions, it is known that Pa 5+ exist in the aqueous phase as either Pa (OH)3 + or PaO(OH) 2+ [6].…”

Section: Methodsmentioning

confidence: 99%